Descriptions need to be pointed - too often I’ve read a description like that of Marbolc and spent the next ten minutes trying to interact with him, only to realize that he’s effectively scenery. Likewise, I’ve spend ages roaming a map trying to find something that was only mentioned in the middle of a room description. If you’re describing something that isn’t important, describe it in such a way that the players can figure that out:
The stream meanders along, far below. The clear, shallow water looks cool and inviting. (This describes the stream, and may set it up for when you light yourself on fire later)
The stream meanders along, far below. (This description tells me about the stream, but it’s short enough that I’ll assume it’s unimportant)
The stream, a tributary of the Greater Sooma, meanders along, far below. The clear, shallow water gently bubbles over smooth stones, glinting in the bright sunlight. Occasionally, a leaf or stick floats by on its surface, or a fish splashes in the shallows. (This stream better be an important part of the story, including floating things in it, catching fish from it, and probably digging up river rocks, and possibly even traveling to the Greater Sooma)
If you wanted the stream to be unimportant in the long run, but still wanted to put in information about it, you should include a dictionary in the game; looking at the stream gives you a basic description, while the dictionary would give you the long, flowing, largely useless prose.
Something else to add - remember that IF can include dynamic statements. As you look at the stream, you could note leaves floating in it one time, a fish the next time, and a frog leaping in the next time. Even if the stream isn’t important, it’s still an active part of the game, and should be used to progress the story. If it’s not part of the story at all, it probably shouldn’t be in the game…